Web feeding and cutting arrangements

ABSTRACT

This invention relates to an arrangement for feeding a web of material through a cutting device. Independently operable withdrawing and guiding means for drawing two webs of material from respective bobbins are provided. Both webs are brought into the vicinity of the cutting device. One web remains at rest, while the other, in an intermittent motion, travels further into the cutting device and is transversely cut by this device during stop periods of this travel. When the trailing end of the first web is detected, indicating that the supply of web from the first bobbin is exhausted, the other web is traversed through the cutting device whilst the first bobbin is replenished.

United States Patent 1191 Demny 1451 Feb. 5, 1974 WEB FEEDING ANDCUTTING ARRANGEMENTS [75] Inventor: Helmut Demny,

Gevelsberg/Westfalen, Germany Related U.S. Application Data [63]Continuation-impart of Ser. No. 838,963, Aug. 12,

1971, abandoned.

[30] Foreign Application Priority Data July 19, 1968 Great Britain34,599/68 [56] References Cited UNlTED STATES PATENTS Small 83/272 X3,160,047 1'2/1964 Malloy et 51 83/65OX Primary Examiner-Frank T. Yost.Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn & Macpeak [5 7]ABSTRACT This invention relates to an arrangement for feeding a web ofmaterial through a cutting device. Independently operable withdrawingand guiding means for drawing two webs of material from respectivebobbins are provided. Both webs are brought into the vicinity of thecutting device. One web remains at rest, while the other, in anintermittent motion, travels further into the cutting device and istransversely cut by this device during stop periods of this travel. Whenthe trailing end of the first web is detected, indicating that thesupply of web from thefirst bobbin is exhausted, the other web istraversed through the cutting device whilst the first bobbin isreplenished.

4 C| aims,3 Drawing Figures PATENTEB B' 51974 INVENTOR HELMUT DEMNYPATENIEDFEB 5:974

saw 2 or z INVENTOR HELMUT DEMNY BY %Z/@W/MI v ATTORNEYS web and to itstravel,

BACKGROUND OF THE INVENTION The invention relates to an arrangement forweb feeding and cutting, the web being of flexible material. Sucharrangements are, for example, used in connection with or form part ofwrapping machines for enveloping articles or collections of articles inflexible wrappers.

-. SUMMARY OF THE INVENTION leading end disposed just short of thecutter. When the trailing end of the first web is detected approachingthe cutter, indicating that one of the bobbins is exhausted, the feeding.means for the first web is rendered inoperative whilst the feedingmeans for the other web is rendered operative.

Advantageously the motion of the web is intermittent and the cuttingoccurs in a motion transverse to the this travel.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION or THE PREFERREDEMBODIMENT Y The embodiment illustrated comprises means in the shape oftwo shafts 1 and 101 for rotatably carrying two bobbins 2 and .102, eachfor storing a web Band 103 respectively. The shaftsl and 101 are mountedon a support 4 the shape of which maybe suited to requirements of eachcase. Rods 5 and 105, rotatably mounted respectively on shafts 6 and 106held by the carrier 4, are provided with rollers 7 and 107 which guidethe webs 3 and 103. The rollers 7 and 107, under the action of suitablespring means (not shown) or under the action of gravity, tension thewebs 3 and 103. Further guide rollers 8 and 108 mounted on the support 4guide the webs 3 and 103 to means for drawing each web from its bobbin 2or 102 respectively, the drawing means being in the shape of two pairsof co-operating rollers 16, 17 and 116, 117 rigidly connected to pairsof normally meshing gear ,wheels 11, 12 and 111, 112. Guiding means 13and 113 guide the webs 3 and 103 so that they approach each other at anacute angle before they reach a reciprocatable cutter blade 14 and areparallel and close to 'each other immediately in front'ofthe cutterblade '14. The cutter blade 14 cooperates with a stationary cutter blade15 (see also FIG. 3). Through a lever arrangement 18 the reciprocatablecutter 14 is operable by an oscillating shaft 19 which is oscillatableby a cam arrangement (not shown) and spring means 22.

The pairs of gear wheels 11, 12 and 111, 112 are driven by a rotatablemain shaft 23 through a gear wheel 24 geared thereto and through furthergear wheels 25, 26, 27, 28 and two electromagnetic couplings 31, one foreach of said pairs of gear wheels 11, 12 and 111, 112. Only one of theelectromagnetic couplings 31 is visible in FIG. 2. The electromagneticcouplings are operable 'by electric coils 32 only one of which isvisible in FIG. 2. The gear wheels 11 and 111 are in operation rotatedonly when the respective electromagnetic coupling is actuated byenergizing its electric coil 32.

Manually operable handles 33, 133 enable the rollers 17, 117 to beremoved against the action of springs 34, 134 from the rollers 16, 116to facilitate the insertion of the webs 3, 103. between the respectivepair of rollers 16, 17 and 116, 117.

during short stopping intervals of Further handles 35, 135 permit therespective pair of rollers 16, 17 or 116, 117 to be manually rotated insteps.

The embodimentdescribed operates as follows:

The webs 3 and 103 are manually drawn from the bobbins 1, 102, passedabout the rollers 7, 107, and the further rollers 8, 108. The handles33,133 are operated so that the rollers of each pair of rollers l6, l7and 116, 117 are distanced from each other, and the leading ends of thewebs are inserted between the rollers of each pair. Subsequently, thehandles 33, 133 are returned to their normal positions so that each web3, 103 is gripped between the respective pair of rollers 16, 17 and 116,117. The handles 35, 135 are; now oscillated whereby the rollers 16, 17and 116, 117 are rotated in steps until the'leading ends of the webs 3,103 travelling through the guiding means 13, 113 lie immediately infront of the cutter 14 One of the electromagnetic couplings 31 isrendered operative by energizing its electric coil 32 so that therespective pair of rollers 16, 17 or 116, 117 starts rotating, therebydrawing one of the webs 3 or 103 past the cutters 14, 15, which areoperated, in a manner known per se to cut predetermined lengths ofwrapping material from the respective web.

When the supply of this web is exhausted the electric coil 32 of one ofthe electromagnetic couplings 31 is de-energized andthe other electriccoil 32 of the other done manually by operating selector switch meansor,

preferably, automatically by means, for example, of photoelectricdevices. A pair of such photoelectric sensing devices are indicatedschematically in FIG. 1 by the light sources 300 and 400 andcorresponding photosensitive receivers 301 and 401. These receiversincorporate suitable amplifying and inverter devices to provide controlsignals which de-energize one of the electric coils 32.0f one of theelectromagnetic couplings 31 and energize the electric coil 32 of theother electromagnetic coupling. The electrical connections between thephotosensitive receivers 301, 401 and the corresponding electric coils32 are not shown in the drawing since these connections and associatedcontrol devices may be of a kind well known per se When one of thephotoelectric sensing devices 300, 301 and 400,

401 senses the trailing end of the corresponding one of the webs 3 or103 approaching the cutter 14, the respective' device provides a controlsignal for deenergizing the electric coil 32 of the correspondingelectromagnetic coupling and energizing the electric coil 32 of theother electromagnetic coupling. This renders the first electromagneticcoupling inoperative and the other electromagnetic coupling operative,This causes the other pair of rollers to rotate so as to draw the otherweb from its bobbin and feed it to the cutters 14, 15. While thiscontinues the empty bobbin 2 or 102 (as the case may be) is removed andreplaced by a fresh, loaded bobbin. Its web is manually passed about therollers 7 and 8 or 107 and 108. The appropriate handle 33 or 133 isoperated so that the nonrotating pair of rollers 16, 17 or 116, -117 aredistanced from each other. When the handle 33 or 133 is returned to itsnormal position, the web is gripped between the non-rotating pair ofrollers'16, 17 or 116, 117. The said non-rotating pair of rollers is nowrotated in steps by manually oscillating 'the respective handle 35 or135. Thereby the leading end of the fresh web is moved'forward.Oscillating of the handle 35 or 135 is interrupted when the leading endof the fresh web is at a short distance of about 1 millimetre from thereciprocating cutter 14. The insertion of the fresh web can be effectedwhile the other web continues to travel beyond the cutters 14 and 15,when the supply of the other web ceases, the electromagnetic couplingsare again actuated so that the pair of rollers rotating up to now arestopped and the other pair of rollers are rotating.

It will be noted that with the embodiment described it is no longernecessary to stop the machine, for example a wrapping machine, to whichthe webs are fed when the supply of web is exhausted and a bobbin has tobe exchanged, nor is it necessary to glue the trailing end of one web tothe leading end of the next web which may necessitate removal of atleast one of the wrapped articles whose wrapping shows the connection oftwo webs as faulty. With the present arrangement the length of the pieceof wrapping material which is cut first from a fresh web is slightlyshorter by about 1 millimetre than the normal length of the pieces. Thissmall difference in length, however, is usually admissible so that forthis reason no wrapped article need be rejected.

Provision is made to interrupt the feed of a web while cutting takesplace. This may be effected automatically by de-energizing therespective coupling while cutting is effected. Alternatively oradditionally, suitable control means 23 may be provided, whereby themain shaft 23 may be rotated intermittently so that, again, the feed ofweb is interrupted while cutting takes place.

What I claim is:

1. A web feeding and cutting machine comprising;

a support;

two rotatable bobbins mounted on said support, each of said bobbinsbeing adapted to store a web;

a pair of pinch rollers corresponding to each of said bobbins andadapted to selectively engage a web stored on the bobbins correspondingthereto, thereby drawing said web therebetween when said pinch rollersare drivenin rotation;

means for driving each of said pairs of pinch rollers;

means corresponding to each of said pairs of pinch rollers for guidingsaid webs from said pinch rollers to a common cutting zone; I

means for cutting'said webs in said common cutting zone; I

means for detecting the end of a web being drawn into said commoncutting zone;

means responsive to said detecting means for automatically stopping thedriving of the pair of said pinch rollers drawing the web the end ofwhich has been detected and starting the driving of the other pair ofsaid pinch rollers; and

manually operable means for rotating' said pairs of pinch rollers,whereby the leading edge of said webs may be positioned immediatelyupstream of said cutting means prior to actuation of said means 1 fordriving said pinch rollers.

2. A web feeding and cutting machine as claimed in claim 1 wherein saidmeans for guiding said webs are adapted to cause said webs to define anacute angle therebetween upstream of said cutting means and to beparallel and close to each other immediately upstream of said cuttingmeans.

3. A web feeding and cutting machine as claimed in claim 1 wherein saidmeans for driving each of said pairs of pinch rollers comprises anelectromagnetic coupling and wherein said detecting means comprises oneor more photoelectric sensing devices.

4. A web feeding and cutting device as claimed in I claim 1 whereinprovision is made to interrupt the feed of web while cutting takesplace.

1. A web feeding and cutting machine comprising; a support; tworotatable bobbins mounted on said support, each of said bobbins beingadapted to store a web; a pair of pinch rollers corresponding to each ofsaid bobbins and adapted to selectively engage a web stored on thebobbins corresponding thereto, thereby drawing said web therebetweenwhen said pinch rollers are driven in rotation; means for driving eachof said pairs of pinch rollers; means corresponding to each of saidpairs of pinch rollers for guiding said webs from said pinch rollers toa common cutting zone; means for cutting said webs in said commoncutting zone; means for detecting the end of a web being drawn into saidcommon cutting zone; means responsive to said detecting means forautomatically stopping the driving of the pair of said pinch rollersdrawing the web the end of which has been detected and starting thedriving of the other pair of said pinch rollers; and manually operablemeans for rotating said pairs of pinch rollers, whereby the leading edgeof said webs may be positioned immediately upstream of said cuttingmeans prior to actuation of said means for driving said pinch rollers.2. A web feeding and cutting machine as claimed in claim 1 wherein saidmeans for guiding said webs are adapted to cause said webs to define anacute angle therebetween upstream of said cutting means and to beparallel and close to each other immediately upstream of said cuttingmeans.
 3. A web feeding and cuttIng machine as claimed in claim 1wherein said means for driving each of said pairs of pinch rollerscomprises an electromagnetic coupling and wherein said detecting meanscomprises one or more photoelectric sensing devices.
 4. A web feedingand cutting device as claimed in claim 1 wherein provision is made tointerrupt the feed of web while cutting takes place.